EG Secure Solutions SiteGuard Server Edition OS Command Injection
CVE-2026-106931 is a high-severity improper neutralization of special elements used in an OS command vulnerability in SiteGuard Server Edition for Apache httpd from EG Secure Solutions, with a CVSS 4.0 base score of 8.5 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version Ver8.00 Update 5 as the first without the flaw, so updating SiteGuard Server Edition for Apache httpd to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on October 20, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update SiteGuard Server Edition for Apache httpd to Ver8.00 Update 5 or a later version.
- Update SiteGuard Server Edition for Nginx to Ver8.00 Update 5 or a later version.
- Update SiteGuard Server Edition for IIS to Ver8.00 Update 5 or a later version.
- CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- Read the advisory on eg-secure.co.jp for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| EG Secure Solutions | SiteGuard Server Edition for Apache httpd | Ver2.20 up to, but not including, Ver8.00 Update 5 | Ver8.00 Update 5 |
| EG Secure Solutions | SiteGuard Server Edition for Nginx | Ver2.20 up to, but not including, Ver8.00 Update 5 | Ver8.00 Update 5 |
| EG Secure Solutions | SiteGuard Server Edition for IIS | Ver2.20 up to, but not including, Ver8.00 Update 5 | Ver8.00 Update 5 |
| EG Secure Solutions | SiteGuard Server Edition for Apache httpd on FreeBSD | Ver2.20 up to, but not including, Ver7.00 Update 6 | Ver7.00 Update 6 |
| EG Secure Solutions | SiteGuard Server Edition for Nginx on FreeBSD | Ver2.20 up to, but not including, Ver7.00 Update 6 | Ver7.00 Update 6 |
| E-guardian | Siteguard | 2.20 up to, but not including, 8.00; 8.00; 2.20 up to, but not including, 7.00; 7.00; 2.20 up to, but not including, 3.10; 4.10 up to, but not including, 8.00 | 8.00, 7.00, 3.10 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (jpcert.or.jp).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.5 | High | CNA (jpcert.or.jp) |
| CVSS 3.0 | 7.8 | High | CNA (jpcert.or.jp) |
Official description
SiteGuard Server Edition contains an OS command injection vulnerability, which may allow an attacker to execute arbitrary OS commands with root or SYSTEM privileges on the system running the affected product.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Record last changed materially (score, affected products, status or references).
- Deadline for US federal agencies to remediate, set by CISA.
References
Third-party and government advisories
- jvn.jp/en/jp/JVN88474777/Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-106931US Government Resource
Our coverage
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 7.2 High severity
- 8.4 High severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
- 9.8 Critical severity
Spotted an error? Tell us.